Accessing Slots
nil
. Consider a frame, v
, that does not have a foo
slot:
v := {name: "Neil", height: 73.25, children: 3}; Print(v.foo);Accessing a nonexistent slot results in the value
nil
; Print
prints nil
.
Because of this, you cannot use the dot operator to distinguish between non-existent slots and existing slots whose values are nil
. To distinguish between the two, you must use the techniques discussed in "Slot Existence" on page 48.
An online version of Programming for the Newton using Macintosh, 2nd ed. ©1996, 1994, Julie McKeehan and Neil Rhodes.
Last modified: 1 DEC 1996